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Re: Chevrolet Volt's Battery Pack re-Ignited

You might want to compare the number of fires caused by gasoline-powered cars versus electric cars. Also, if there's been a fire in your garage and you just leave your electric car with it's case of li-ions parked in it for several days, you should not be allowed to be a firefighter..

Re: Chevrolet Volt's Battery Pack re-Ignited

Originally Posted by tolkaze

Surely they wouldn't, it would be lighter, cheaper and safer to build their own large capacity prismatic cells.

While I'm guessing GM may not make their own cells, it certainly seems like it is a prismatic pack. wikipedia quotes it as a 16KwH pack with 288 cells, 55.5 Wh/Cell would be 3.7V @15AH, so either prismatic Li-Ion, or possibly M sized cylindrical cells.

Re: Chevrolet Volt's Battery Pack re-Ignited

Originally Posted by Wrend

Congratulations.

Thank you. I recently got my car back from the collision shop after it was involved in a fender-bender. Nothing exploded during the mild contact. I've had a garaged parking spot for the past decade. Two different models in that 10 year period. Both proven technology gas-engine only models. I sleep very soundly at night.

It's nice relying on technology that has been time proven and tested for more decades than most drivers have been alive. But hey, feel free to roll the dice with your life if that's your choice. Stay classy.

"The World is insane. With tiny spots of sanity, here and there... Not the other way around!" - John Cleese.

Re: Chevrolet Volt's Battery Pack re-Ignited

As someone who works at a GM Dealer, I am not impressed by the Volt. It is an overpriced vehicle that had a HUGE amount of tax dollars invested in its development, is receiving huge tax breaks at our expense to spur sales to high income purchasers, and uses technology that may never trickle down to an affordable vehicle. It is a prime example of government intervention in an attempt to sell the public something they cannot afford and at this point in time do not want. It is also a highly technical vehicles whose short term reliability has not been all that good (50% of our Volts have had significant electrical issues) and whose long term reliability (as the electronics, wiring connections, and cooling systems age) will be questionable at best. When the $55,0000 Tahoe Hybrid came out we were told that the technology would eventually be mass produced and used in less expensive vehicles. Sound familiar? It was a GREAT premise as the Hybrid Tahoe delivered a SOLID 20 MPG in city driving. Yet the technology never trickeled down. Instead GM pushed for the Volt and now the new E-Assist, which is an affordable compromise but is far from a true hybrid.

At this point in time I do not believe that the Volt battery packs are unsafe. We have not seen issues in that area. We have seen issues in some of the subsystems necessary to support the use of that battery pack as well as some of those required to operate the vehicle. That said, I would not park one in my garage. There are other hybrids out there that are much more affordable and far less risky in the long term.

I would make a slightly different bet: that all-electric vehicles are inevitable, but that they require the invention of an energy storage system that may be nothing like a battery.

The energy density of even the best batteries is just terrible -- a few hundred Wh/kg vs. 13,000 Wh/kg for gasoline. Eight gallons of unleaded contains one gigajoule of energy, and you can pump the stuff (or "recharge" the gas tank) at a rate of 10 GPM, which is 20 megawatts. Carbon-based fuels have their problems, but any serious attempt to replace them must begin with an appreciation of how bloody amazing they are.

Re: Chevrolet Volt's Battery Pack re-Ignited

Having sufficient capacity and capable enough batteries isn't an issue; it's the cost of having that higher capacity. I think batteries will continue to get less expensive and electric cars more viable because of that.

Also, comparing energy per mass between batteries and gasoline isn't completely relevant. Batteries are rechargeable, and gasoline isn't, and you can of course recharge batteries with gasoline and use them to drive in an electric car about as efficiently as using the gasoline in an ICE car, if you want to. The energy in batteries is used significantly more efficiently than the energy in gasoline.

Re: Chevrolet Volt's Battery Pack re-Ignited

Originally Posted by flashflood

The energy density of even the best batteries is just terrible -- a few hundred Wh/kg vs. 13,000 Wh/kg for gasoline. Eight gallons of unleaded contains one gigajoule of energy, and you can pump the stuff (or "recharge" the gas tank) at a rate of 10 GPM, which is 20 megawatts. Carbon-based fuels have their problems, but any serious attempt to replace them must begin with an appreciation of how bloody amazing they are.

You're forgetting the mass of the internal combustion engine and transmission here. The electric motors which drive an electric car weigh a fraction of what an internal combustion engine weighs. That means even with the poor energy density of the batteries, a battery-electric car may not necessarily weigh more than its ICE counterpart.

That being said, when you consider that EVs are "almost there" even with batteries of a few hundred Wh/kg, imagine what would happen if we break 1000 Wh/kg. EVs with 500 to 1000 mile range would exist, making the need to fast charge moot. And this would make ICEs totally obsolete except for niche uses.

Re: Chevrolet Volt's Battery Pack re-Ignited

Originally Posted by jtr1962

You're forgetting the mass of the internal combustion engine and transmission here. The electric motors which drive an electric car weigh a fraction of what an internal combustion engine weighs. That means even with the poor energy density of the batteries, a battery-electric car may not necessarily weigh more than its ICE counterpart.

That being said, when you consider that EVs are "almost there" even with batteries of a few hundred Wh/kg, imagine what would happen if we break 1000 Wh/kg. EVs with 500 to 1000 mile range would exist, making the need to fast charge moot. And this would make ICEs totally obsolete except for niche uses.

Oh, I agree -- the vastly simpler mechanics are why I think electrics will win in the end.

But batteries are only "almost there" if the car is small, uses low-rolling-resistance (and thus nothing like Z-rated) tires, never accelerates aggressively, doesn't run the A/C full-blast, etc. Even then, it requires massive taxpayer subsidies. There is something very wrong with Tesla buyers getting a $10,000 tax break, paid for by people who are struggling to scrape together half that much to buy a used car.

Electric cars will have truly arrived when people start buying them because they are flat-out better than gasoline cars: faster, cheaper, more comfortable (no more transmission hump!). That day will come, but batteries -- or some other form of energy storage -- will have to get a *lot* better to make it happen.